Scott Vacuum engine, copying

[gary hart]

Scott Vacuum engine copy cat.

Four years ago finished  a fabricated Scott Vacuum engine.  Didn't have plans but there was enough pictures and dimensions in John  Bogstandard's  build article "Scott Flame licker (vacuum engine).

http://www.modelenginemaker.com/index.php?topic=158.0

The cylinder block with water hopper was silver soldered using brass. The cylinder was what had on hand aluminum. Has 1-1/2" bore instead of 1-5/16" bore but kept the 2" stroke.  Mock up to see if things will work together.  Propane burner as per John's instructions.



The piston is made from graphite.  Instead of using a wrist pin in piston decided to try a ball joint.  Low load on piston and solves some possible alignment problem.



Graphite block for the slide valve.  Spring holds graphite to head.



Got it to run when put together,  but not very good.  Went ahead and painted it and couldn't get it to run after painting.  Shoved it to the back and it sat until   Stilldrillin (David D)  posted changing the valve and preventing the exhaust and valve movement from interfering with the flame.

http://www.modelenginemaker.com/index.php?topic=4270.0

Copied David's slide valve, flame shield and exhaust opening.   Liked the twin ports and twin burner tubes, copied them also.   Took the easy way and used the old valve linkage with little modification.





For adjustable flame made moveable tubes that slide over the outside of the wicks instead of having the wicks move.



<a href="https://www.youtube.com/watch?v=iAT2V8MpctE" target="_blank">http://www.youtube.com/watch?v=iAT2V8MpctE</a>
Longer YouTube
<a href="https://www.youtube.com/watch?v=CPcLn-Gpk3A" target="_blank">http://www.youtube.com/watch?v=CPcLn-Gpk3A</a>

[Kim]

That's really beautiful Gary!  And an amazing runner.  Very smooth, and it will stay running at such a slow speed.  That's just amazing!

Thanks for sharing the pics and video with us!
Kim

[fumopuc]

Hi Gary, a very smooth runner. Well done. Congratulations.

[b.lindsey]

That is some amazing slow speed running Gary!! In the earlier pictures you showed a spring holding the graphite to the head. It now appears that the actuating bar runs beneath the side levers rather than above them (as shown in your third photo), but no spring now. In making the changes, what now holds the graphite against the head?

Love the color too btw.

Bill

[Dave Otto]

Very nice Gary!

Thanks for posting the pictures and videos.

Dave

[gary hart]

Bill,  the new valve is a copy of Stilldrillin (David D) where the graphite block is replaced by a flat spring that rides up and down in a loose fitting groove.
 Vacuum and a pushing of valve towards head on the upstroke makes for a good seal.

Don't know why for sure but this is the only vacuum engine that I have that will start while cold and not need any preheating.

Gary

[b.lindsey]

Thanks for the clarification Gary, I do recall what David had done too but wasn't sure if your had eliminated the graphite or not. Honestly I have never seen a better vacuum engine running consistently (and so well) at such low rpm's. Well done!!

Bill

[Tennessee Whiskey]

Gary, the wick adjusting mechanism is brilliant and that sound is as soothing as a carriage horse's hoofs on the cobblestone  .

Cletus

[Don1966]

That's a smooth runner and a beauty Gart. Love the color and the craftsmanship is superb..............I like...............

Don

[tvoght]

It looks and runs great, Gary. Thanks for showing it.

--Tim